Stapling device

ABSTRACT

The stapler includes a staple advancing system for applying an advancing force to a plurality of &#34;U&#34; shaped staples (19); a guide (16) for maintaining said plurality of &#34;U&#34; shaped staples (19) parallel to each other along a feed axis, said guide (35) having a channel cross section (33) including a horizontal top portion, substantially perpendicular to said feed axis, and two semi-vertical portions (37) below said horizontal top portion, each having a plane oriented downwardly inward at such an angle which does not cause plastic deformation of said &#34;U&#34; shaped staples (19) inserted in said guide (35), said guide (35) having an open end wherein said semivertical portions (37) merge with vertical portions (39) having walls which are substantially vertically aligned; a lower aperture (6) aligned along said feed axis with said vertically aligned walls; and a displaceable staple ejector (2) without displacing an adjacent &#34;U&#34; shaped staple (19).

This application is a 371 of PCT/US95/00112 filed on Jan. 4, 1995, whichis a continuation-in-part of application Ser. No. 08/177,262, filed onJan. 4, 1994, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a stapling device. More particularly,the stapling device has a unique configuration, suitable for use as atissue proximation device, an endoscopic surgical microstapler for theattachment of tissues such as for the reanastomosis of gastrointestinalorgans and gynecological procedures with "B" shaped staples. The stapleralso has an improved feed and insertion mechanism.

BACKGROUND OF THE INVENTION

Surgery often involves the reattachment or reanastomosis of variousinternal tissues or organs, especially in the later stages of a surgicalprocedure, e.g. during closure. This tissue fastening may also be aprimary object of a surgical procedure, or merely incidental thereto.Presently, there are a number of methods available to perform thistissue proximation and attachment. These include the use of singlefilament sutures, braided sutures, dissolvable sutures, permanentsutures, steel sutures, staples, clips, dissolvable plastics, permanentplastics, surgical adhesives and other methods. Many of these proceduressuffer from the limitations that their applicability is limited, or theprocedure is time consuming and requires great skill.

A number of fastener types are available having differing shapes. Eachfastener type has properties which determine its applicability, anddiffering fasteners generally have differing insertion methods andapparatus.

The relevant prior art includes U.S. Pat. No. 3,225,996, GB 1,095,441and CA 186,605. In addition, United States Surgical Co. has developedvarious surgical staplers, CMT-0,15 (prior to 1972), CMT-0,25 andCMT-0,4 (prior to 1968, U.S. patent application Ser. No. 108,566) andCMT-3 (prior to 1972, U.S. patent application Ser. No. 312,602, May 22,1972).

The art has been presented with some difficulties relating to tissueproximation and attachment during endoscopic or laparoscopic procedures.These difficulties may be related to organ manipulation limitationsposed by conventional endoscopic instruments. For example, with a dualincision procedure, it is difficult to retain organs in an appropriateand anatomically correct position for the time necessary to complete theattachment. Therefore, endoscopic procedures have evolved in a mannerwhich minimizes the need for extensive organ reattachment orreanastomosis employing the endoscopic instrument. Tools have been madeavailable to perform such procedures quickly and efficiently, but as aresult the versatility may be of narrow scope. Procedures which do notfall within the scope of available endoscopic instruments must beperformed as full open field surgical procedures. Intestinalreanastomosis may be accomplished by way of intraluminal techniques;however, the available instrumentation tend to be highly specialized forthis purpose.

The art also teaches stapling techniques for fastening co-planar sheets,as in the conventional desktop office stapler. The conventional staplerhas a number of elements. First, the staple itself is generally a steelwire bent into a U-shape having 90° bends at the corners. The staplernormally includes a sequential feed for a plurality of staples, whichare aligned parallel to each other in a feed channel. The channel ofstaples is fed sequentially to an active region of the stapler by aspring, providing an advancing force from a rear hinged proximal portiontoward a distal end, from which the staples are ejected. The hingeconnects and maintains in proper alignment, the staple ejectionmechanism with a former element (hereinafter a "former") which sitsbelow the tips of the distal-most staple with the staple feed mechanism.When the two hinged portions, the staple ejection mechanism and theformer, are pressed together, first the tips of the staple engage theitem to be stapled, in alignment with the former. Next, a hammer memberhaving a thickness approximately equal to that of a single staple,presses the staple downward, out of vertical alignment with the channelformed by the supply of staples in reserve, and through the item. As thestaple penetrates the item, the tips engage the former and are curved inan inward direction antiparallel toward each other, so that the top ofthe staple remains substantially straight, while the corners are bentfrom their 90° configuration to approximately 180° angle with the topportion, with a gentle curvature, in a "B" shape. If the item is thick,then the prongs of the staple penetrate substantially parallel with eachother, and the penetrating portions are curved after penetrating theitem. The office stapler thus has two phases of operation: first, thetwo hinged portions move toward each other to surround the item; second,the staple is ejected and penetrates the item to be fastened and theends bent inward toward each other. These movements are controlled by afirst spring force between the hinged portion between the staple feedmechanism and the former, and a second spring force, greater than thefirst spring force, between the pushing element and the staple feedmechanism. Because of the characteristics of the steel wire, thefocussed bending caused by the action of the former causes a plasticdeformation. Thus, the staple retains its bent shape after the former isremoved. The staple also has elasticity, allowing some play andflexibility of the item after stapling. A "B" shaped staple, because ofthe elastic recoil of the bent legs, has self adjusting properties. Thestaple is confined in the active region of the stapler by the adjacentstaple on one side and a wall on the other. The staple is generally heldin vertical alignment with the adjacent staple by an adhesive whichbinds the channel formed by the staples. The pusher, generally havingthe thickness of a single staple, pushes the staple which sits in theactive region, shearing the adhesive, and the staple moves downwardthrough a gap. This arrangement is subject to jamming from variouscauses. For example, two staples may enter the active regionsimultaneously, or the steel wire may be sheared by the pusher.

It is also known to form an office stapler using, instead of a channelshaped series of staples, a feed wire, which forms staples in situ. Thefastener element feed of this type of stapler is somewhat different fromthe previously described type. The wire is fed from a coil, and is fedto lie substantially parallel to the plane of the objects to befastened, extending over a form. As the mechanism is activated, the wireis cut to length, and bent over a rectangular form, to form as anintermediate stage a "U" shaped staple. The form is removed from thepath of the staple, and the tips are projected toward the former, anddeformed thereby after penetrating the objects to be fastened. Thesewire-form staplers may use a brass wire, supplied from a coil, insteadof a steel wire. In a wire-fed stapler, the length of the staple legsmay be adjusted between fastenings by determining the length of the cutwire and its positioning during the process.

Surgical staplers are also known for the closure of skin incisions.These staplers differ from office staplers in that they operate withouta former portion analogous to that described above. The staple consistsof a bent piece of steel having inwardly radially curved downward memberwith a straight top connecting member. The connecting member is bent inthe middle prior to insertion. For application, the tissues areproximated, with the skin edges slightly everted, and the staplingdevice placed above the incision. The staple is then un-bent tostraighten the top connecting member, causing the radially curvedportions to penetrate the tissue and hold the tissues in place. Theseincision closure staples are intended to be removed by a special devicewhich bends the staple in the middle to disengage the downwardprojecting legs. This type of staple is especially useful for skinclosure of abdominal incisions. Various other types of fasteners,including "V" shaped, box shaped, and clips are also available.

Instrument sets are available to perform intestinal resections andreanastomoses. These instruments may use specially designed tissueconnection devices. These instruments must, however, be speciallydesigned for a given procedure and the procedure must be performedclosely following the standard for that instrument, or rather, theinstrument defines a portion of the procedure, and may only be used ifthe patient meets certain criteria for application of the device. Thesedevices apply a fastening element array in a single action and thuscannot necessarily apply an optimal or controlled traction of thetissues for each fastening element or portion of the closure. Thus, thetissue between the fastening elements may be damaged or suboptimallyfixed by the fastening, with the possibility of increased hemorrhagingor tissue necrosis.

SUMMARY OF THE INVENTION

The present invention includes a staple insertion mechanism and methodof use thereof which applies surgical titanium wire staples to fastentissues. The instrument carries a plurality of staples, which aresequentially inserted, and has an 11 mm diameter shaft adapted forendoscopic use through a trochar sleeve. The instrument operates bytransmitting a mechanical force from an actuator, through elements inthe shaft, to a stapling device in a head portion of the device. Theaction initially causes a closure of elements which position the tissueto be joined between the staple and the former. In a second phase ofoperation, further action causes the staple to be advanced through thetissue and causes the ends to be bent by the former to fasten thetissues. In a preferred embodiment, a sliding cylindrical sleeve effectsthe first and second phase of operations.

The preferred configuration of the stapler has an elongated shaft withan 11 mm outer diameter, for insertion in a standard 10-11 mm ID trocharsleeve. Standard trochar sleeves include sealing elements, e.g. rubberO-rings, for sealing against gas leakage from the body cavity when anappropriate device is inserted in the sleeve or when it is removed. Thecylindrical construction of the elongated member of the device allowssealing against the O-rings, preventing the release of gas from, forexample, an inflated abdominal cavity, by providing close tolerancesbetween the outer surface of the stapler and the inner surface of thetrochar sleeve. The stapler itself prevents substantial passage ofgasses or liquids internally. If the trochar sleeve does not includesuch an O-ring, an appropriate sealing device may be included in thestapler. The construction also allows free rotation and variable lengthof insertion of the stapler within the trochar sleeve, and rotation ofthe stapling head with respect to the handle mechanism. Thecharacteristics of the abdominal wall allow for free angular movement inspace of the stapler tip, within the trochar sleeve, to allow access toa large portion of the abdominal cavity. Of course, the present stapleris not limited to abdominal procedures, and may be used i in thoracic,retroperitoneal, plastic surgery and other types of surgery. Thus, thetip of the stapler may be positioned within the abdominal cavity withfour degrees of freedom, approximating a polar coordinate system with anadditional angle of the stapler within the trochar sleeve. In anotherembodiment, the stapler tip may be articulated, providing furtherdegrees of freedom.

The preferred embodiment of the present invention, the stapler containsa staple cartridge, which may hold between 1 and 200 staples, morepreferably between 10 and 50 staples, and most preferably 20 staples.These magazines are preferably interchangeable, and an appropriatequantity of staples in a staple magazine may be selected by the surgeonimmediately prior to use. Cartridges are preferably intended for asingle use, e.g., for use during a single surgical procedure, afterwhich the cartridge is disposed, and a new sterile cartridge is placedfor the next patient. The cartridge includes the staple feed mechanismas well as the pusher and former. The handle, trigger and actuationportions may be reusable, but it is preferred that these portions alsobe disposable. The staple cartridge may also be an integral portion of adisposable device.

The stapler, due in part to the length of the arm holding the formermember and its clearance from the core portion of the magazine, canattach tissues having a range of thicknesses. For example, a preferredembodiment of the stapler according to the present invention canaccommodate tissues in excess of a total of about 4.0 mm in combinedthickness tissues for attachment, so long as the tissues may becompressed to about 2.5 mm, the clearance between the former arm and thebody of the stapler, without permanent damage to the stapling mechanism,or substantial unintended tissue damage. The minimum tissue thickness ispreferably about 0.5 mm. Thinner tissues tend to be more fragile and maybe damaged by the staple and stapling mechanism. In addition, very thintissues often do not require a sturdy proximation device and a delicatetechnique is preferred. For tissue thicknesses in excess of about 3.0mm, a larger stapler is preferably employed, which has increasedclearances and employs larger staples. Thus, the stapler according tothe preferred embodiment of Example 1 is designed to accommodate a rangeof tissue thickness, and may be modified according to the present designprinciples to perform a wide range of surgical procedures. The presentstapling process possesses a significant tolerance, such that the tissuethickness may vary from about 0.5-2.5 mm, compressed tissue thickness,which corresponds to a greater thickness range, up to about 4 mmthickness uncompressed, depending on the organ.

The staple according to the preferred embodiment, is formed from asurgical titanium wire, the preferable staple having a width of 3 mm(the top bridging portion), a height of 4 mm (the length of the leg) anda wire diameter of 0.2 mm. The preferred titanium alloy wire forfabrication of the staples is 40KXHM. The staples may be formed in astandard manner, by bending a wire over a form having broken sharpedges, with an angle of about 90°, which rebound to an angle of slightlygreater than 90°. In the preferred embodiment, the legs are bent, afterforming, to about 105° from the horizontal (the top bridging portion).In the preferred embodiment, the wire diameter for the staples may varyfrom 0.15-0.2 mm, without modification of the design. Staples smallerthan about 0.15 mm or larger than about 0.2 mm require modifications tothe design of the stapler, especially the staple feed and insertionmechanism.

The surgical stapler consists of two major assemblies: first, a handlewith a tube like body, having a trigger element connected to anactuation linkage. The second element is a magazine filled with aplurality of staples, a pushing element for extracting staples from thestapler and pushing them towards a former. The staple magazine ispreferably detachable and interchangeable, allowing multiple uses of thehandle assembly with a disposable or interchangeable staple cartridge,which is attached to the tube-like body of the handle through a coaxiallinkage with a spring loaded catch. Because of the medical applicationof this device, the staple magazine has been designed for a single use,thus reducing the problem of ensuring sterility and eliminating staplejams. As stated above, a fully disposable design may include an integralstaple cartridge.

The handle of the stapler is preferably ergonomically adapted for manualuse by a surgeon, in order to enhance the functional usefulness of thedevice and to reduce the probability of error. The trigger, dependentfrom the handle, is also ergonomically adapted for depression by thesurgeon with his index finger, or combination of index and middlefinger. The depression force of the trigger should thus be great enoughto prevent accidental activation of the device, yet low enough to allowrepeated stapling operations without strain or cramping of the surgeon'shand. The mechanism is designed so that an initial depression of thetrigger with respect to the handle causes a movement of elements of amechanical linkage, which acts to hold the tissue in place andsubsequent depression causes insertion of the staple by advancing thestaple legs through the tissue, so that the legs are bent by the formerafter penetrating the tissue.

In various embodiments according to the present invention, the triggermay be passively linked to the stapling head, wherein all of the forcesand power necessary for stapler operation are derived from the trigger.The trigger may also be linked to control a power source in an activelyassisted system. In such instance, the trigger depression provides onlya part or none of the stapling operational power. It is preferred thatthe trigger be provided with a means for providing a force feedback fromthe stapling head to the surgeon's hand. This allows force feedback tothe surgeon's hand, which enhances the feel of the device, and providesgreater safety due to better control by the surgeon. This force feedbackmay be a mechanism directly linked to the stapling head, or asynthesized force based on a sensor and feedback actuator.

The staple magazine has a channel with an approximately "U"-shape. Aninner portion inside an outer portion defines a trapezoidal "U" shapewith the tips of the "U"-shape closer together than the length of thetop bridging portion. The staple magazine is charged by elasticallycompressing the legs of the "U"-shaped fasteners together to approximatethe trapezoidal shape of the channel, to provide clearance for insertionof the staple into the channel. Thus, with the end plate removed,staples are sequentially inserted into the shape-conformed cavity, withcare being taken to hold previously inserted staples in place while anext staple is inserted. The first staple inserted presses against atrapezoidal shaped form linked to a feed spring, and which transmits thespring force. The spring force is likewise transmitted through anystaples in the channel to the staple adjacent to the active staple (thelast staple inserted), which, in turn, is pressed against an end plate.Of course, other staple insertion methods are possible, which willresult in a similar final configuration.

Thus, when inserted in the channel-like cavity, the staples have but asingle degree of freedom, advancing along a horizontal or longitudinalaxis of the stapler due to the staple feed spring. The active staple hasan additional degree of freedom. In addition to having an axis ofmovement along the longitudinal axis of the stapler, constrained by theend plate, it also has a movement along the vertical axis of thestapling head, which is defined by a recess in the end plate, thepusher, and a lower aperture. The active staple is prevented fromfalling out of the lower aperture by the frictional forces (e.g. it isforce locked) of the adjacent staple, pressed against it by the springforce, and the walls of the recess of the end plate. If necessary, theactive staple may also be held in place by a form lock system, having amechanical linkage which releases the staple as the pusher beginsadvancing toward the former.

The stapler may also include a plurality of staple channels, forsequential insertion of a plurality of staples. In this configuration,the staples may advance along parallel or antiparallel paths, with aformer having a plurality of forming surfaces. For example, six staplesmay be simultaneously inserted in a staggered double row in a singleoperation, in so-called "chess" fashion. The stapler includes threeparallel feeds from one side, and an additional three parallel feeds,staggered from the first feeds, from the other side. These staples will,in this configuration, generally feed perpendicular to the longitudinalaxis of the stapler shaft.

The pusher system may also be formed differently in order to reduce themaximum diameter of the device. For example, a pair of sector gears,pivoting lateral to the staple channel, may be employed to eject thestaple. A linear pusher may also be displaced by small gears lateral tothe staple channel.

The optimal angle of bending of the legs of the staple while in thetrapezoidal feed is determined by the material of the staple and itsconfiguration. This angle should be such that the tips of the stapleadjacent to the active staple are medial to the tips of the activestaple by at least the diameter of the wire from which the staple isformed. The gap formed by the first recess is preferably slightly deeperthan the gauge of a single staple to provide clearance, butsubstantially smaller than the combined width of two staples. Themaximum deformation is limited by the elastic deformation limits of thestaple, however. If the staple is bent too far, then it will bedifficult to release the staple from the feed into the active position,due to a too great frictional force and the possibility of plasticdeformation of the staple thereby preventing expansion to aperpendicular state. Because the staple is retained in the feedinitially by the presence of the active staple, and then by the pushingelement, when the pushing element is returning to its resting positionabove the staple, the tips of the adjacent staple will be forced by boththe feed spring and the differential release of tension on the tips ascompared to the top bridging portion. Thus, the adjacent stapleundergoes a complex, dynamic-angular movement into the active position,which further helps to accurately position the active staple and preventinterference from the new adjacent staple.

The trapezoidal shape may be constant over the length of the feedchannel, or be tapered. If tapered, it is preferable that the feedchannel taper inwardly.

A catch or lock mechanism may be provided to prevent advance of astaple, so that the stapler may be inserted and removed from the trocharsleeve without undesired ejection of staples. This catch or lock may bemanually engaged, or automatically engaged by the presence, absence ortransition of the trochar sleeve. Alternatively, the staples may beplaced in the feed channel alternating with dummy staples which areformed of a biocompatible or dissolvable composition. Therefore, thestapler may be removed between each staple insertion. If the pusher armis eliminated and replaced with a different type of ejection system,such a catch or lock, or alternating staple system may be avoided.

The staples may be automatically inserted in the magazine, eliminatingthe need for manual insertion and the concomitant problems of ensuringcleanliness and sterility. Otherwise, the staples may be manuallyinserted into the guide channel of the staple magazine. For insertion, abiocompatible adhesive may be employed to adhere a plurality of staplesin parallel, so that they may be loaded together. This adhesive may thenbe removed, such as by a solvent, to leave the staples in their free,independent state.

When the pusher advances downward along the stapling head vertical axis,it sits in a second, deeper recess in the end plate, and initiallycontacts the top bridging portion of the staple, that part which bridgesthe two legs. The second recess is deeper and narrower than the firstrecess, and the lateral walls have a tight clearance to the pusher. Thedepth of the second recess is such that it protrudes about one staplewidth into the first recess, so that only a single staple restingagainst the end plate will be vertically displaced, and any adjacentstaple will not be disturbed. Thus, the pusher in the second recess isflush with the inner face of the end cap. As the pusher advancesvertically downward, the sharpened points of the legs of the stapleemerge from the lower aperture of the stapling head, aligned with thevertical axis thereof.

When the operator presses the trigger, the bottom surface of the pusherelement contacts the top of the active staple in the magazine. Theactive staple is seated in a recess in the end cap, which guides thestaple vertically. The pusher is seated in a deeper recess in the endcap, so that the pusher may have a width greater than the width of thestaple. The pusher does not advance the staple adjacent to the activestaple because the width of the pusher is carefully controlled to beequal to the depth of the recess plus the width of the active staple.The staple tips are forced into the tissue matrix located between thestaple tips and the former, and begins to penetrate.

In operation, the tissues to be attached lie in parallel planesimmediately below the advancing staple and between the lower apertureand the former. The tips of the staple thus pierce the first tissue,emerge from the first tissue and pierce the second tissue. The tips ofthe staple, upon emerging from the second tissue, are in contact withthe former. The tips of the legs of the staple follow a curvelinear pathdefined by the former, and curve upward, preferably again passingthrough the layers of tissue, depending on the thickness of the tissueand length of the staple legs. The tips may extend beyond the topbridging portion, and for this reason a gap is formed in the centralportion of the pusher to provide adequate clearance for the staple tipsas they are directed upward. After the former is released, the bentstaple legs may rebound, and in fact the "B" shape allows a selfadjustment of the staple to the tissue thickness. If desired, the formermay be displaced a desired distance from the staple ejection port, toallow control over the location of the staple tips after forming. Theformer displacement may be adjustable between stapling operations.

The former is a hard steel element having a pair of somewhatellipsoidally curved indentations, which are aligned adjacent, withtheir long axes parallel to each other. The indentations are configuredto have a curvature having a radius smaller than the desired finalconfiguration, so that it rebounds to the desired shape due toelasticity of the staple wire. The indentations preferably have agradually decreasing radius of curvature toward the center of theformer. The angle of the indentation with respect to horizontal is about20° at the lateral aspect, and about 45° at the medial aspect along thecenterline of the indentation. The walls of the indentations are eachformed of five substantially planar faces, a horizontal lower face, twocanted walls, on either side of the horizontal lower face, which areinclined about 45° from vertical, having planes which intersect belowthe indentation, and two upper walls which are parallel and are about 7°from vertical, having an intersection below the indentation, thusforming a piecewise approximately concave configuration of theindentation, when viewed in cross section.

The optimal staple configuration, after forming in the stapler, is asomewhat rectangular shape, with a straight top bridging portion, havingrelatively sharp square bend at the corners, formed in the originalproduction of the "U"-shaped staple, with the legs curved semicircularlyup toward the center of the top bridging portion. The tips of the legpreferably extend to about the position of the top bridging portion,making a second pass through the tissues in the central region, but mayextend to a point before or after intersecting the top bridging portion.As stated above, the position of the tips may be controlled by adjustingthe position of the former during stapling. The legs have a gentlercurvature toward their ends than at the preformed corners.

It should be noted that, biologically speaking, tissues having a largeconnective tissue or muscular wall width tend to be subjected to greaterforces than those with thinner walls. Thus, the proximation ofthick-walled organs preferably should be performed with a larger gaugewire staple, with a greater length between the legs in order to achievemaximum strength and most efficient closure. Long-legged thin wire gaugewire staples tend to have their tips wander off their optimal pathduring insertion, so that care should be taken in selecting the staplefor use in procedures involving particularly thick, dense or muscularorgans.

The gauge of the staple wire is determined by the geometry of thestaple, the material characteristics, and the intended application. Ofcourse, the stapler must be designed for a particular staple or staplesize, and therefore the selection of a stapler limits the choice ofstaples which may be used. In a preferred embodiment, a 0.2 mm diametertitanium wire is used. The tissues to be proximated are usuallyintestine, but may be other tissues, including stomach, esophagus,reproductive organs, muscle, fascia, omentum, lung, bile duct, renalpelvis, ureters, bladder, blood vessels, etc. For, e.g., thereanastomosis of ileum, where the lumen wall has a width of about 2 mm,a surgical titanium staple having legs 4 mm long and 0.2 mm diameter ispreferred. While the free tissues have a thickness together of 4 mm, thestaple is primarily intended to join the adventitia layers, and maycompress the other tissue layers, which will overgrow the staple inhealing. Thus, in healing, the staple may be embedded in the tissue. Forstapling parts of the stomach subject to great stresses, it is preferredthat a larger staple having greater strength is used. This is becauseportions of the stomach are muscular, having a thick muscular layer, andmay be subject to almost continuous and powerful contractions.

By the present principles, the stapler according to the presentinvention could be scaled to specifically accommodate general gastricsurgery; however, tests have been conducted with good results using thestapler according to the present invention for a posteriorpyloric-duodenal anastomosis.

The elongated body of the stapler consists of an inner core, slidablewith respect to an outer concentric sleeve. The sleeve terminates in apair of cam-like shaped edges, a top edge and a bottom edge. The topedge is aligned with the pusher arm, while the bottom edge is alignedwith the former arm. The pusher arm has a return spring and is linked tothe pusher, such that a depression of the pusher arm toward the corecauses the pusher to advance downward along the vertical axis in thesecond recess of the end cap, between the end cap and the staple feedchannel. The former arm also has a spring return and terminates in theformer. When depressed toward the core, the former aligns with the pathof the staple tips. The sleeve edges are so shaped that, with the coreof the staple magazine holding the pivot points of the arms in fixedrelation, and therefore displaceable along the longitudinal axis withrespect to the outer sleeve, the former arm is pressed by the relativelyadvancing edge of the outer sleeve toward the core before the pusher armadvances the pusher to advance the staple downward. This sequence isdetermined by the shape of the surface of the pusher arm, the shape ofthe surface of the former arm and the shape of the top and bottom edgesof the sleeve. The pusher arm has three portions of its surface, a firstportion with a narrow angle with respect to the longitudinal axis, ashort second portion, distal to the first portion which has a steepangle, and a third portion, distal to both the fist and second portions,which has an narrow angle. Thus, the advance of the outer sleeve overfirst portion of the pusher arm causes little depression of the pusherarm, the advance of the outer sleeve over the second portion with asteep angle causes a rapid depression of the pusher arm midway throughthe stroke to push the staple down into the former to deform the stapleinto its final configuration, and the further advance of the outersleeve over the pusher arm has little effect, but provides assurancethat the stapling cycle is completed and the staple properly fastened.In contrast, the former arm has essentially a single, mild angle withrespect to the longitudinal axis, and the former thus advances towardthe staple and is completely in position prior to initial depression ofthe pusher arm. The return spring of the former arm has a low springtension, while the spring tension for return of the pusher arm is high.

Because of the relatively high force exerted by the sleeve against theaxially moving spring loaded arms, the relatively thin sleeve should beformed of a tough material. The base of each of the arms preferably havea smooth surface finish, in order to reduce the wear on the sleeve dueto surface irregularities. In a reusable stapler configuration, the armmaterial should be softer than the sleeve, as any wear of the arm basewill be more distributed and less troublesome than wear of the sleeveedge. These conditions may be determined, for example, by using acold-rolled steel sleeve and cast arms.

While the preferred embodiment represents a direct mechanical linkagebetween the handle/trigger mechanism, other sources of power arepossible. These power sources include electrical, hydraulic, pneumatic,stored mechanical energy, as well as, in certain circumstances, storedchemical and explosive chemical energy. Initially, it is noted that thepower source may be stored in the handle, a simple proposition due tothe fact that less than 200, and preferably only 20 to 50 staples needby inserted. Otherwise, the energy source may be external to thestapler, and electrical, hydraulic, pneumatic or mechanical energytransmitted to the stapler through a tether cord.

Any form of stored energy may reside in or near the handle, and betransduced into mechanical energy in the handle portion, and thereforethe remainder of the operational details are essentially identical tothe stapling system of the aforementioned preferred embodiment.Alternatively, the transducer may reside closer to the stapling head, inthe elongated member or in the head itself. Further, the transducersystem may form a functional part of the stapling system, and replace ormodify various mechanical features of the above described preferredembodiment.

An electrically operated embodiment according to the present inventionemploys an electrical power source located in the handle to providepower to an electromechanical transducer. The power source may be, e.g.,a primary battery or a rechargeable battery. The handle of the staplerhas, mounted at the front portion thereof, and extending downward, anelectrical switch. The switch preferably has a safety interlock whichprevents accidental activation of the stapler during use.

A first electrically powered embodiment makes use of a motor, whichdrives a helical screw gear, causing a linear movement of a follower.The follower is linked to an assembly which causes closure of thestapling head. Completion of a stapling operation is detected by a limitswitch, which initiates a reversal of the motor, bringing the system tothe starting position, which may be detected by a second limit switch.Thus, the closing and opening action are automatically determined.

Alternatively, the helical element may be dual-cut, to provide automaticreturn without need for reversing the motor. This arrangement furthereliminates the need for one of the limit switches, particularly the onewhich detects maximum excursion. Further, since the return strokerequires less torque than the excursion/stapling stroke, the return maybe faster, e.g. a steeper helix, than the stapling stroke.

A second electrically powered embodiment may be constructed using asolenoid driven actuator. The solenoid may be a linear-acting unitlocated in the base of the elongated member, operated to longitudinallydisplace the core with respect to the sleeve. A plurality of solenoidactuators may also be employed to individually control the pusher andformer, and possibly accessories of the device.

In an pneumatic embodiment according to the present invention, themotive force for the stapling mechanism is provided by a source ofcompressed air. The source can be a compressed gas cylinder contained inthe handle, an internal pump, or an external source fed by a tube fromoutside the device. The compressed gas is used to move a piston in acylinder, which, in turn, actuates the stapling mechanism. The pistonmay be located in the handle or near the stapling cartridge. The triggeractuates a valve, which vents gas into the cylinder, moving the piston.The return stroke can either be implemented by a spring, acting againstthe piston, or by use of a double acting cylinder. In either case, thegas must vent from the cylinder at the completion of the stroke. In adouble acting cylinder embodiment, the gas moves the cylinder forward,until a valve opens at the end of the stroke. The valve vents the gas.Simultaneously, the outer cylinder is connected to the compressed gas,wherein it returns to the starting position, and the gas vents. The gasmay vent to the atmosphere near the cylinder, or be shunted away.

The force for driving the stapling mechanism may also be hydraulic. Thesource of power for this hydraulic system may be a trigger mounted pump,which incidentally may also be analogously used for a pneumatic-pumpbased system. Alternatively, the system may have an external source ofhydraulic power. Because hydraulic fluid is incompressible, the use of ahydraulic systems also allows miniature hydraulic actuators to beincorporated in the stapling head. These miniature cylinders may beseparately actuated and controlled, giving fine control over theoperation of the stapler and any associated devices. Hydraulic fluidmust be contained in a closed system, and should not be vented, unless aphysiologic solution is used.

The stapler of the present invention may advantageously be adapted toinclude tissue forceps, for holding the two layers of tissues to bejoined in place and under appropriate tension for the staplingoperation. These forceps would consist of one or two active forcepssystems, for holding the tissue layers either individually or together,at points on either side of the stapling head. Advantageously, theseforceps systems would be individually controlled by cables, rods,cylinders or solenoids and would lock closed when the tissues are inplace, to be unlocked selectively after stapling. This forceps systemshould have, in addition to the closing action, at least one axis ofmovement so that the tension on the tissue may be controlled. Becausethe stapling mechanism is normally used sequentially, it is advantageousif the forceps mechanism provides for an advancing of the stapling headwithout a requirement for unlocking and repositioning of the staplinghead. This may be provided, for example, by allowing movement of theforceps mechanism with respect to the stapling head with tissue lockedin place.

The forceps included with the stapling mechanism may also be used forother purposes in the surgical procedure. Likewise, the present staplingmechanism may be combined with other known endoscopic instruments in asingle apparatus having enhanced functionality. These instrumentsinclude cameras, illuminators, forceps, biopsy tools, cautery, clipapplicators, laser surgical tools, etc. Optical elements may be locatedwith an optical axis longitudinally oriented at the tip of the device,or positioned to be used to illuminate or view the tissue being stapled.

The present stapling device provides a hinged former. However, theformer may also be linked to the core of the device by a multilinkarticulated mechanism which provides a substantially linear movementbetween the core and former. Such a mechanism is particularlyadvantageous with an inserter for variable length staples, such as mightbe possible with an in situ formation of staples, or a multiple feedmechanism with a plurality of staple sizes. In such instances, theformer would be accurately positioned with respect to the staple feedmechanism regardless of the thickness of the tissue, which could be inexcess of 5 mm in such an embodiment. When a variable length staple isemployed, the travel of the pushing element preferably also adapts tothe length of the leg of the staple.

Of course, it should be realized that, while the various embodimentsaccording to the present invention include provision for inserting onlyone staple at a time, the present invention could also be adapted toperform a tissue proximation by inserting two or more staplessimultaneously.

OBJECTS OF THE INVENTION

Therefore, it is an object of the present invention to provide asurgical stapler according to the apparatus of claims 1 to 7 and themethod of claims 8 to 10.

It is also an object of the present invention to provide a staplerincluding (a) a manually operable mechanism producing an actuationsignal; (b) an actuation signal transmission system; (c) a staplecartridge, comprising: (i) a staple advancing system for applying anadvancing force; (ii) a longitudinal guide, for maintaining a pluralityof U-shaped staples parallel to each other along a longitudinal axis;(iii) an end guide, having a vertical axis, said vertical axis beingsubstantially orthogonal to said longitudinal axis, a first recessaligned with said vertical axis and a second recess, deeper than saidfirst recess, aligned with said vertical axis; (iv) a lower aperture,aligned with said vertical axis; and (v) a displaceable staple press,displaceable along said vertical axis in said second recess, and guidedthereby, being for displacing a staple along said vertical axis withoutvertically displacing an adjacent staple; (d) a displaceable former, forplastically deforming staple ends, said former being displaceablebetween a first position in which the former is substantially displacedalong said vertical axis from said end guide and a second position inwhich the former is substantially proximate to said end guide; and (e)control means for displacing said former from the first position to saidsecond position prior to displacing said staple press toward said formerby moving said press arm.

It is a further object of the invention to provide a surgical staplercartridge, comprising: (a) a staple advancing system for applying anadvancing force; (b) a longitudinal guide, for maintaining a pluralityof staples parallel to each other along a longitudinal axis, said guidehaving a horizontal top portion, substantially perpendicular to saidvertical axis, and two semi-vertical portions, each having a planeoriented downwardly inward at such an angle which does not cause plasticdeformation of a staple inserted in said guide, having an open endwherein said semivertical portions merge with vertical portions havingwalls which are vertically aligned; and (c) an end guide, having avertical axis, said vertical axis being substantially orthogonal to saidlongitudinal axis, a first recess aligned with said vertical axis and asecond recess, deeper than said first recess, aligned with said verticalaxis; (d) a lower aperture, aligned with said vertical axis; and (e) adisplaceable staple press, displaceable along said vertical axis in saidsecond recess, and guided thereby, being for displacing an active staplealong said vertical axis without vertically displacing an adjacentstaple, said active staple being confined upwardly by said staple press,laterally by walls of said first recess, and rearwardly by said verticalwalls of said open end of said longitudinal guide.

A still further object of the present invention is to provide a methodof attaching biological tissue, comprising the steps of: (1) providing astapler having a stapling cartridge, (2) placing the tissues to beattached along the vertical axis of the staple press, between the stapleand the former; (3) displacing said former from the first position tosaid second position in a first phase without substantially displacingsaid staple press; and (4) displacing said staples press toward saidformer to displace a staple by moving said press arm in a second phase,after said former is in said second position.

It is a still further object according to the present invention toprovide a wire feed stapler, in which a linear wire is cut to length andbent into a "U" shape, prior to insertion in which the staple legs aredeformed by a former to fasten the tissue.

The present invention may also include a staple ejection mechanism inwhich a portion of the mechanism resides lateral to the staple feedchannel, to allow a reduced instrument diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are shown in the figures in thedrawings, in which:

FIG. 1 is a cutaway side view of a handle of a preferred embodiment ofthe present invention;

FIG. 2 is a cross section along H--H through a hinge portion of FIG. 16;

FIG. 3 is a cross section along D--D through a catch portion of FIG. 12;

FIG. 4 is a cross section along A--A through a collar portion of FIG. 1;

FIG. 5 is a cross section along I--I through a spring portion of FIG.16;

FIG. 6 is a representative cross section through the channel portion ofthe staple feed mechanism;

FIG. 7 is a cross section along B--B through a set screw portion of FIG.1;

FIG. 8 is a cross section along C--C through the handle body portion ofFIG. 1;

FIG. 9 is a cutaway side view of the end cap along AA--AA of FIG. 10;

FIG. 10 is a front view of the end cap;

FIG. 11 is a cross section along E--E through a trigger hinge portion ofFIG. 1;

FIG. 12 is a side, partial cutaway view of the stapling portion of apreferred embodiment of the present invention in an open condition;

FIG. 13 is a side, partial cutaway view of the stapling portion of theembodiment of FIG. 12, in a closed condition;

FIG. 14 is a top cross section view along F--F (FIG. 1), G--G (FIG. 12);

FIG. 15 is a side view of a preferred embodiment of the presentinvention;

FIG. 16 is a side cross section view of the staple magazine assemblyaccording to the present invention;

FIG. 17 is a cross section along L--L through a pusher mechanism of FIG.16;

FIG. 18 is a cross section along K--K through a staple channel of FIG.16;

FIG. 19 is a cross section along J--J through a staple feed mechanism ofFIG. 16;

FIG. 20 is a cross section along M--M through an end cap mechanism ofFIG. 16;

FIG. 21 is a side view of the staple magazine assembly;

FIG. 22 is a top view of the staple magazine assembly of FIG. 21;

FIG. 23 is a cross section along Y--Y of FIG. 22;

FIG. 24 is a cross section along Z--Z through a catch portion of FIG.21;

FIG. 25 is a top view of the handle;

FIG. 26 is a bottom view of the cover;

FIG. 27 is a cross section along Q--Q of FIG. 30;

FIG. 28 is a cross section along R--R of FIG. 30;

FIG. 29 is a bottom view of the magazine body;

FIG. 30 is a side view of the magazine body;

FIG. 31 is a top view of the magazine body;

FIG. 32 is a cross section along P--P of FIG. 30;

FIG. 33 is a cross section along S--S of FIG. 31;

FIG. 34 is a cross section along BB--BB of FIG. 37;

FIG. 35 is a cross section along T--T of FIG. 37;

FIG. 36 is a front view of the handle;

FIG. 37 is a side view of the handle;

FIG. 38 is a side view of the magazine body;

FIG. 39 is a top view of the magazine body;

FIG. 40 is a cross section along W--W of the magazine body of FIG. 39;

FIG. 41 is a cross section along U--U of FIG. 38;

FIG. 42 is a cross section along X--X of FIG. 40;

FIG. 43 is an end view of the magazine body;

FIG. 44 is a front view of a staple;

FIG. 45 is a side view of a trapezoidal sheet;

FIG. 46 is an end view of a trapezoidal sheet;

FIG. 47 is a top view of the block;

FIG. 48 is a side view of the block;

FIG. 49 is a cross section side view of the block and trapezoidal sheet;

FIG. 50 is an end view of the cover and internal staple guide;

FIG. 51 is a front view of the pusher;

FIG. 52 is a cross section along CC--CC of FIG. 51;

FIG. 53 is an end view of the block;

FIG. 54 is a cross section along V--V of FIG. 38;

FIG. 55 is a front view of the former;

FIG. 56 is a top view of the former;

FIG. 57 is a cross section along N--N of FIG. 59;

FIG. 58 is a cross section along O--O of FIG. 57;

FIG. 59 is a detail top view of the former;

FIG. 60 is a partial cutaway side view of a hydraulic embodimentaccording to the present invention;

FIG. 61 is a partial cutaway side view of a hydraulic embodimentaccording to the present invention including a double-acting cylinder;

FIG. 62 is a partial cutaway side view of staple sensing embodimentaccording to the present invention;

FIG. 63 is a partial cutaway view of an electrical embodiment accordingto the present invention;

FIG. 64 is a partial cutaway view of an electrical embodiment accordingto the present invention;

FIGS. 65 and 65A are partial cutaway views of a pneumatic embodimentaccording to the present invention;

FIG. 66 shows a top view of an embodiment of a staple feed channel inwhich the staples are angulated with respect to the longitudinal axis ofthe staple feed channel;

FIG. 67 shows a top view of an embodiment of a staple feed channel inwhich staples are angulated with respect to the longitudinal axis of thestaple feed channel and rotate to a position perpendicular to the staplefeed channel for insertion;

FIG. 68 shows a detail cross section through a staple insertion portionof an embodiment of a stapler in which sector gears, pivoting aboutpoints lateral to the staple feed channel eject the staple; and

FIG. 69 shows a detail cross section through a staple insertion portionof an embodiment in which the pusher is displaced by sets of gearsplaced lateral to the staple feed channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1

FIG. 1 shows a side view of a preferred surgical stapler embodiment ofthe present invention, for sequentially inserting and forming a singlestaple at a time. FIG. 1 shows the construction of the device. The outerdiameter of the shaft of the stapler is 11 mm, for insertion in an 11 mmID trochar sleeve. The construction of the device provides sealing,preventing the release of gas from, for example, an inflated abdominalcavity, by providing close tolerances between the outer surface of thestapler and the inner surface of the trochar sleeve. The constructionalso allows free rotation of the stapler within the trochar sleeve androtational freedom of the stapling head with respect to the handle.

The mechanism at the tip of the device actually need be no wider thanthe staple and the necessary supporting sidewall. Thus, with a 3 mmstaple, the width of the tip need only be 1-2 mm wider than the staple,or 4-5 mm total.

In this embodiment, the magazine is adapted to hold about 20 staples,although only minor changes relating to the characteristics of thestaple feed advance mechanism are necessary in order to adapt themagazine for between 1 and about 200 staples. In this embodiment, themagazines are interchangeable, and a cartridge containing the desiredquantity of staples may be selected by the surgeon immediately prior touse.

The stapler, because of the length and compliance of the arm holding theformer member, can attach tissues having a range of thicknesses. Thepresent stapler can accommodate tissues between 0.5-2.5 mm compressedthickness tissues for attachment.

The staple itself is formed from a surgical titanium wire, thepreferable staple having a width (crossmember length) of 3 mm, a height(leg length) of 4 mm and a wire diameter of 0.2 mm. The presentembodiment may accommodate staples having shorter legs, and a wirediameter as little as 0.15 mm. The staples may be formed in a standardmanner, by bending a wire over a form having broken edges, to produce a"U" shaped structure having legs splayed outward at an angle of 105°from the crossmember.

The staples, while in the magazine, have their legs inwardly bent,having an angle with respect to the upper connecting portion of thestaple of about 85°, thus forming a trapezoidal structure. In theirunconstrained state the staples have an angle of about 105°. Therefore,the staples are held in place through a frictional force against theside-wall of the channel, pressed against the side wall by the inherentspring force of the titanium wire. The bending forces exerted on thestaple legs while retained in the channel are such as to apply anelastic deformation force without plastically deforming the staple.Further, this bent leg configuration assists in ensuring that only asingle staple is engaged for ejection at any time by the pushingelement, because it is separated from the pack of staples behind it bythe termination of the feed channel into the end cap. The end cap at theend of the feed channel has an area for expansion of the staple to aperpendicular (90°) angle of the legs to the top bridging portion. Thisarea of expansion also provides a further force inhibiting the forwardmovement of the staple adjacent to the active staple, since only asingle staple can be present in the area of expansion at any given time.Thus, the active staple is separated from the remaining staples and hasa different configuration. When the active staple is removed, or moreproperly, on the upstroke of the pushing element, the adjacent staple ismoved to the active position by the spring force, and its legs expand toa perpendicular state.

The surgical stapler consists of two major assemblies: first, a handlewith a tube like body, possessing all necessary elements forfunctionality, provided in a manner adapted for a series of staplingoperations, and second, a magazine filled with a plurality of staples, apushing element for extracting staples from the stapler and pushing themtowards the former. The staple magazine is replaceable andinterchangeable, allowing multiple uses of the handle assembly with adisposable staple cartridge, which is inserted within the tube-like bodyof the handle. Of course, the handle may also be disposable, andintegral with the cartridge.

The handle 10 is adapted for being comfortably held in a surgeon's hand.Thus, an ergonomic design is applied to make the instrument comfortableand functionally appropriate in use. This handle 10 is connected bymeans of a transversely oriented pin 13 to the trigger 11, The trigger11 is also ergonomically designed, so that the handle 10 and trigger 11are together optimized for repeated use in the surgeon's hand. Thetrigger 11 is functionally linked to the pushing element, so that arelative movement of the handle 10 toward the trigger 11, e.g., bysqueezing them together, causes, through a mechanical linkage, theformer 4, mounted on a former arm 5, to move to a position proximate tothe lower aperture 6 and the pusher 2, linked to a pusher arm 3, toeject the active staple 20 through the tissue and toward the former 4.

The magazine assembly 1 is held in fixed position by a spring loadedcatch 18 in spring recess 17, in the magazine body 16, insertedcoaxially and engaging a proximal outer sleeve of the handle assemblythrough an aperture 18' in the wall of the tube. The spring loaded catch18 must be depressed in order to be inserted or removed from themagazine assembly 1. When inserted, the magazine assembly 1 is placedcoaxially inside the outer sleeve 15, and moves to an extended positionwhen the catch 18 lines up with the aperture 18' in the wall of theproximal outer sleeve 14, to achieve a form lock.

The handle 10 is connected by screw fasteners to the handle body 9.Inside the handle body 9 is a displaceable member 7 with a return spring8. The return spring 8 is a helical spring concentric around anelongated stock 12, which is fixed in place by a set screw 21 mounted inthe handle body 9. The stock 12 is coaxial and inside the displaceablemember 7. The displaceable member 7 is moved in response to a movementof the trigger 11 with respect to the handle 10. The trigger 11 has, atits upper end, a yoke 22 adapted to displace the displaceable member 7without limiting its rotational freedom. The displaceable member 7 thushas rotational freedom of 360°.

The displaceable member 7 is rotatable about its long axis within thehandle body 9, and is in fixed rotational orientation with respect to arotatable collar 23. The displaceable member 7 has a pair of channels 24which allow longitudinal displacement of the displaceable member 7 withrespect to the rotatable collar 23, which is linked to a proximal outersleeve 14, by set screws 25 which further sit in the pair of channels24. The proximal outer sleeve 14 terminates a distance from therotatable collar 23. At the termination of the proximal outer sleeve 14,the outer sleeve 15, which is fixed to the displaceable member 7,emerges. The proximal outer sleeve 14 and the outer sleeve 15 arecoaxial and have the same diameter, thus ensuring a seal duringendoscopic procedures. Prior to the termination of the proximal outersleeve 14, there is an aperture 18' which is unobstructed by thedisplaceable member 7 therewithin.

The magazine assembly 1 has a magazine body 16, having a proximalportion in which the spring loaded catch 18 is placed. The magazine body16 is of such configuration as to fit within the outer sleeve 15 and aportion of the proximal outer sleeve 14.

From the magazine body 16 emerges on a top aspect a pusher arm 3, havinga return spring 26 pressing it outward. From a bottom aspect of themagazine body 16 emerges a former arm 5, also having a return spring 27pressing it outward. Both the former arm 5 and the pusher arm 3 pivotabout an axle 28 within the magazine body 16.

The magazine body 16 is hollow in a distal portion, covered by a cover29. The hollow section contains the staple feed mechanism. The staplefeed mechanism consists of a helical staple feed spring 30 pressingagainst a block 31 having a trapezoidal sheet 32 elongated extensionwhich slides within a staple channel 33, thus pushing the staples 19within the channel 33. The trapezoidal sheet fits 32 around the block31, and are held together by soldering. Alternatively, the block may beformed integral with a bent portion of the trapezoidal sheet. The staplefeed channel 33 is oriented such that the top portion of the staples 19are under the pusher arm 3.

The staple feed spring 30 and block 31 are held within the hollowsection by the cover 29 which terminates at a distal portion in an innerstaple guide 35, which, together with the hollow section, forms a threesided U-shaped trapezoidal aperture which is the staple feed channel 33,which terminates in a space 34 provided in an end cap 36. The end cap 36has a first vertical recess 37, which forms the space 34, having a pairof vertical walls 38 and a depth of about the width of one staple 20,and certainly significantly less than two staples 19, 20. Thus, with a0.2 mm staple width, the first vertical recess 37 is about 0.22 mm deep.The end cap 36 has a second vertical recess 39, for guiding the pusher2, which is deeper and narrower than the first vertical recess 37. Thesecond vertical recess 39 has a depth such that the pusher 2 does notinterfere with the end of the magazine body 16, and thus clears the laststaple 19 in the U-shaped trapezoidal aperture which is the staple feedchannel 33. The pusher 2 is a rectangular block which slides within thesecond vertical recess 39. The bottom portion of the pusher 2 has acentral recess 40 to provide clearance for upturned tips 44 of a staple20 at the end of a stapling operation.

In operation, the trigger 11 is depressed and the outer sleeve 15advances with respect to the staple magazine assembly 1, which is heldby the spring loaded catch 18 in the aperture 18' of the proximal outersleeve 14. The outer sleeve 15 initially presses against the former arm5, which is pressed against the magazine body 16 and assumes anorientation parallel to the longitudinal axis of the staple magazineassembly 1. The tissues to be fastened are held between the former 4 atthe end of the former arm 5 and the cover 29 on the bottom of the staplemagazine assembly 1.

Further advance of the outer sleeve 15 rapidly presses the pusher arm 3downward, against the magazine body 16, such that the pusher 2 isdepressed fully, thereby expelling the active staple 20, which isdeformed by the former 4. Further advance of the outer sleeve 15 haslittle effect, but provides an overtravel region which assures properfastening.

The magazine assembly 1 is constructed as follows. The magazine assemblyconsists of a magazine body 16, which is securely connected to andcovered with cover 29. Staples 19, having a "U" shape, are held in themagazine body 16 by the trapezoidal sheet 32 linked to the block 31 atthe end of the staple feed spring 30 on one end, and the end cap 36 onthe other end. The staples 19, 20 are confined in a channel 33 in themagazine assembly 1 formed by a magazine body 16, having a hollowtrapezoidal space having the desired configuration, and an inner blockwhich is the inner staple guide 35, to prevent rotational misalignmentof staples 19 within the channel 33, also having a solid, roughlytrapezoidal form with some clearance for ease of movement of the staple.The inner staple guide 35 is affixed to the block by screws 41. Thedefined space between the magazine body 16 and inner staple guide 35,having the staples 19, has a profile such that the end of the dependentlegs of the fasteners 19, e.g. the wire ends, after being charged intothe magazine assembly 1, are held constrained, having their dependentlegs compressed toward each other, from their free-state "U" shape.

The magazine assembly 1 is charged by compressing the legs of the "U"shaped staples 19 together to provide clearance for insertion of thestaple 19 into the channel 33 of the magazine body 16. Thus, with theend cap 36 removed, staples 19 are sequentially inserted into thechannel 33, with care being taken to hold previously inserted staples 19in place while a next staple 19 is inserted. The first staple insertedpresses against the staple feed spring 30, and transmits the springforce, used to advance the staples, to the active staple 20 (mostrecently inserted), which is held in place by the end plate 36. Ofcourse, other method o staple insertion are possible.

Thus, when inserted into the channel 33 cavity, the staples 19 have buta single degree of freedom, advancing along a horizontal or longitudinalaxis of the stapler. The active staple 20 in the first vertical recess37 has an additional degree of freedom. In addition to having an axis ofmovement along the longitudinal axis of the stapler, constrained by theend plate 36, it also has a movement along the vertical axis of themagazine assembly 1, which is defined by the first vertical recess 37 inthe end plate 36, the pusher 2, and the lower aperture 6. The activestaple 20 is prevented from falling out of the lower aperture 6 by thefrictional forces (e.g. force locked) of the adjacent staple 19, pressedagainst it by the spring force, and the vertical walls 38 of the firstvertical recess 37 in the end plate 36. Since the free expansionconfiguration of the staple 19, 20 has an angle of 105° between the topbridging portion 42 and the legs 43, the legs press outwardly againstthe vertical walls 38 of the first vertical recess 37. If necessary, theactive staple 20 could also be held in place by a form lock system,having a mechanical linkage which releases the staple 20 as the pusher 2begins advancing toward the former 4.

When the former 4 advances downward along the magazine assembly 1vertical axis, it initially contacts the top bridging portion 42 of thestaple 20, which bridges the two legs 43. In actuality, the pusher 2 hasa central recess 40 or void in the middle, so that it applies a downwardforce at the lateral portions of the staple 20. The top bridging portion42 will tend to bow slightly upward when the legs 43 are pressedtogether. The downward force is applied and distributed evenly to thestaple legs 43 by the pusher 2.

The pusher 2 sits in the second vertical recess 39 in the end plate 36,such that it abuts the end of the staple channel 33, and thereby clearsthe staple 19 adjacent to the active staple 20. The pusher 2 does noteject the staple 19 adjacent to the active staple 20 because the widthof the pusher 2 is carefully controlled to be equal to the full depth ofthe second vertical recess 39, which is approximately equal to the depthdifference between the first vertical recess 37 and second verticalrecess 39 plus the width of the active staple 20. The staple tips 44 areforced into the tissue matrix located between the staple tips 44 and theformer 4, and the staple tips 44 begin to penetrate.

The pusher 2 continues to advance, such that the sharpened tips 44 ofthe legs 43 of the staple 20 emerge from the lower aperture 6 of themagazine assembly 1, aligned with the vertical axis thereof. Inoperation, the tissues to be attached lie in parallel planes immediatelybelow the tips 44 of the advancing staple 20 and between the staple 20and the former 4. The tips 44 of the staple 20 thus pierce the firsttissue, emerge from the first tissue plane and pierce the second tissueplane. The tips 44 of the staple 20, upon emerging from the secondtissue plane, are in contact with the former 2.

The former 2 is a hard steel element having a pair of asymmetricallycurved indentations 45, which are aligned adjacent, with their axesparallel to each other. The indentations 45 are somewhat wider than astaple, with almost vertical sidewalls 46. The indentations 45 areplaced such that the outer portions of each indentation are aligned withthe expected positions of the staple tips 44. Thus, upon contacting theformer 4, the staple tips 44 are curved toward each other, due to thedownward force of the pusher 4 and the bending force of the surface ofthe indentation 45. As the staple 20 further advances, the tips 44eventually reach the nadir 47 of the semi-ellipsoidally configuredindentations 45, with the tips 44 advancing antiparallel, and the tips44 then follow the curvature of the indentations 44 so that they turnand begin to advance upward. The radii of curvature of the formerindentations 45 is selected such that the deformation exceeds theelastic deformation limits of the surgical titanium wire from which thestaple 20 is formed. Thus, the staple legs 43 are plastically deformedand will substantially retain their bent shape after the former 4 isremoved. The radius of curvature decreases toward the center 48 of theformer 4, thereby causing the staple tips 44, as they emerge from theformer 4, to be pointed upward. Because the staple 20, after beingdeformed by the former 4, has some resiliency, the former 4 is designedso that an optimal shape of the staple 20 is obtained after the former 4is removed. This means that the former 4 should have a shape which has aconformation with a smaller radius of curvature than is ultimatelydesired, so that it rebounds to the desired shape. The ultimate shape ofthe staple 20 will, of course, depend on the staple material andconfiguration, the former 4 configuration, and the tissues beingfastened.

The stapler is designed to accommodate a range of tissue thickness.First, the length of the staples 19, 20 may be selected by the surgeonprior to use, based on the properties of the tissue to be connected,although a 3 mm by 4 mm by 0.2 mm staple should suffice for mostprocedures. Second, the stapling process possesses a significanttolerance, such that the tissue thickness may vary substantially from0.5 to 4.0 mm. In one embodiment according to the present invention, theformer 4 may be displaced from its fully closed position during staplingin order to control the position of the staple tips 44 in the tissueafter stapling.

The design according to the present embodiment is adapted in certainrespects for small scale production, and of course it should be realizedthat the design may be advantageously modified for production on alarger scale without changing the fundamental aspects of operationaccording to the present invention.

The preferred embodiment of the present invention is fabricatedcompletely from stainless steel, with the various springs being madefrom stainless steel adapted for use in springs, which may be fabricatedin known manner from standard materials. The structural portions of thedevice according to the present invention may also be fabricated fromplastics, with a particularly preferred material being Kaprylon®, withthe exception of the springs, outer sleeve for depressing the former armand pusher arm, the former and former arm and the pusher and pusher arm.The staple magazine body is particularly preferred to be formed ofplastic. When constructed from various medically suitable plastics, theapparatus may be assembled using standard plastic fabricationtechniques, including bonding, molding, fasteners and form lockconfigurations.

Example 2

The present embodiment employs an electrical power source located in thehandle to provide power to an electromechanical transducer, formed as alinear-acting solenoid at the base of the core of the elongated shaft.The handle of the stapler has, mounted at the front, and extendingdownward, a member which activates an electrical switch. The switchpreferably has a safety interlock which prevents accidental activationof the stapler during handling. The stapling head employed isessentially similar to the stapler of Example 1.

The present embodiment, shown in FIGS. 63 and 64 consists of a magazineassembly 1, an outer sleeve 15, a tube-like body 49, an electricalrotary motor 50, a handle 10, an electrical power source 51, anelectrical connection system 52, a trigger button 53, an electricalswitch 54, a helical gear 55, and a limit switch 56. The principal ofoperation of the present embodiment is the use of a motor 50, whichdrives a helical screw gear 55, causing a linear movement of a follower57. The follower 57 is linked to an assembly which causes closure of thestapling head, as described above with respect to Example 1. Completionof a stapling operation is detected by a limit switch 56, whichinitiates a reversal of the motor 50, bringing the system to thestarting position, which is detected by a second limit switch 58.

Alternatively, the helical gear may be replace with a dual-cut helicalcam-follower system, to provide automatic return without need forreversing the motor. This arrangement further eliminates the need forone of the limit switches 56, particularly for detecting maximumexcursion. Further, since the return stroke requires less torque thanthe excursion/stapling stroke, the return may be faster, e.g. a steeperhelix, than the stapling stroke.

Further, the former may be positioned at a desired displacement from theclosed position in order to control the position of the staple tipsafter stapling. Likewise, the pusher may be stopped short of full travelto control the position of the staple tips. Either of these may beaccomplished by providing a clutch and mechanism to separate themovements of the pusher arm and the former arm, and controllingengagement of the clutch. When the pusher travel is controlled, theouter limit point may also be varied to effect the control, without aclutch.

In addition, an alternative embodiment is provided with its source ofelectrical power by a wire from a standard power supply or speciallydesigned motor controller.

Example 3

In a second electrically powered embodiment of the present inventionshown in FIG. 62, a sensor 59 is present which serves to prevent theinsertion of staples 20 immediately on top of one another. This systemworks by incorporating a sensor 59 in the magazine assembly 1 generallyaccording to Example 1, preferably near the lower aperture 6, near thepoint of exit of the staples 20, or alternatively in or near the former4. Basically, a sensor 59 detects the change in electromagneticproperties of the medium surrounding the sensor 59, due to the presenceof the surgical titanium wire of a previously inserted staple 20. A bulkconductivity sensor may also be employed, based on the difference inconductivity of the staple 20 and the tissues in which it is inserted,measurable due to the substantial length of the top bridging portion 42of the staple 20. The system may be employed as a failsafe doubleinsertion preventing system with automatic operation, or merely as anindicator to the surgeon. This same sensor may also be used to ensurethat a staple is present at a sensed location, which may be obscuredduring use.

The stapler according to the present, sensor-equipped embodiment,includes a magazine assembly 1, an outer sleeve 15, a tube like body 49,a sensor 59, a handle 10, an electric connection system 52, an electricseparator 61, a light source 60, a functional electric block 62 and anelectric power source 51.

The device is essentially the apparatus according to either of Example 1or Example 2. The sensor 59 is designed so that it reacts based onproximity of a previously inserted staple 20. In this embodiment, thestaple proximity detector does not automatically prevent insertion, butrather has an annunciator to visually, e.g., the light source 60, orauditorily signal the surgeon of the proximity of a staple 20.

The electrical connection system 52 and the electric separator 61 act inconjunction to produce a signal, which is transmitted to the functionalelectric block 62 which produces an indication on trigger button 53 orany other known indicator, including an audible alarm, signaling thesurgeon that he must relocate the stapling assembly in any direction, toprevent a chance of inadvertent repeated installation of a staple in thesame place.

Example 4

In the present example, as depicted in FIG. 65, the motive force for thestapling mechanism is provided by a source of compressed air, e.g., acompressed gas canister 63 in the handle 10. The magazine assembly 1 isessentially identical to the embodiment according to Example 1. Thecompressed gas from the canister 63 is used to move a piston 64 in acylinder 65, which, in turn, moves the displaceable member 7 withrespect to the proximal outer sleeve 14. The trigger 11' actuates avalve 66, which causes compressed gas to enter the cylinder 65, movingthe piston 64. The return stroke is implemented by a spring 67, actingagainst the piston 64, but a double acting cylinder 68 may alternativelybe useful for this purpose. In either case, the gas must vent from thecylinder 65 at the completion of the stroke. The gas moves the piston 64forward, until a vent valve 69 opens at the end of the stroke. The ventvalve 69 vents the gas. In a double acting cylinder 68, simultaneouslywith venting of the actuator cylinder 65, the return cylinder 70 issupplied with the compressed gas by a control valve, causing the systemto return to the starting position, at which time the gas in the returncylinder 70 vents through vent valve 69'. The gas preferably vents nearthe handle body 9.

The embodiment according to this pneumatic embodiment comprises amagazine assembly 1, an outer sleeve 15, a tube-like body 49, a returnspring 67, a handle 10 assembly, a piston 64 in a cylinder 65 in thehandle body 9', a vent valve 69, a compressed gas canister 63, a trigger11' and an actuation valve 66.

In operation, the surgeon presses trigger 11', causing the actuationvalve 66 to be opened. The actuation valve a predetermined quantity ofgas to pass from the gas canister 63 into the cylinder 65 of handle body9'. The compressed gas in the cylinder 65 acts on the piston 64, whichfurther exerts a force which is transmitted to the displaceable member7, closing the stapling mechanism as described above. The gas vents atthe peak excursion of the piston 64, and the piston 64 returns to thestarting position by means of a helical return spring 67 acting on thepiston 64. The stapler is then in condition for a next staplingoperation. The vent valve 69 is activated at the apex of the cylinderexcursion by known means.

Example 5

The force for driving the stapling mechanism may also be hydraulic. Thesource of power for this hydraulic embodiment is a trigger 11 mountedfirst pump 73, although an external source of hydraulic power with atrigger actuated valve may be employed. Because hydraulic fluid 72 isincompressible, the use of a hydraulic systems also allows miniaturehydraulic actuators to be incorporated in the stapling head. Theseminiature cylinders may be separately actuated and controlled, thusallowing independent control of the pusher, former, as well asarticulation, auxiliary devices such as forceps, rinse valves, suturingdevices, etc.

The magazine assembly 1 of the present embodiment, shown in FIG. 60 isessentially identical to the embodiment according to Example 1. Theconstruction of the hydraulic embodiment comprises a magazine assembly1, an outer sleeve 15, a tube-like body 49, hydraulic fluid 72, a handle10, a return spring 67', a first pump 73 with piston 74, a handle body9, a trigger 11 and a handle 10. The use of a fluid drive facilitatesthe use of flexible supply hose with a remote hydraulic actuator, whichwill allow a flexible endoscopic stapler with force feedback to thetrigger. Hydraulic fluid is not generally vented, and therefore residesin a closed system. Of course, a biologically compatible fluid may beemployed which may be vented within a body cavity.

In an alternative embodiment, as shown in FIG. 61, the return spring 67'is replaced by a compressible gas 75 which, when compressed, exerts areturn force on the piston 74.

Example 6

In order to reduce the width of the stapling device, the staple in thefeed channel may be skewed, as shown in FIGS. 66 and 67. The staples inthe guide are inclined with respect to the feed axis, in order to reducethe width of the device. At the tip of the device, the staple may beinserted at the inclined angle, as shown in the configuration of FIG.66, or shifted into a position orthogonal to the feed axis, as shown inthe configuration of FIG. 67.

In the embodiment according to FIG. 67, the staple legs need not beinwardly bent, in order to ensure reliable feed. The skew of the staplesmay provide the necessary differentiation to ensure a reliable feed. Thestaple angulation zone 6701 may be separated from the staple feed zone6702 by a pair of ridges 6703, 6703'.

In order to reduce the height of the mechanism, staples may be inclinedvertically, and inserted along an inclined axis or vertically realigned.When inserted inclined, the staple press also moves along an inclinedaxis, reducing the vertical travel distance. While the inclination maybe at any angle, an inclination of 30° is preferred.

Example 7

The staple ejection mechanism may be provided as a low profilemechanism, as shown in FIGS. 68 and 69. As shown in FIG. 68, a pair ofsector gears 6801, 6801', which respectively rotate about axes 6802,6802', located laterally to the staple feed channel. The sector gearseject the staple 19 in the active region, while retaining the staples 20in the feed channel. The rotating sector gears 6801, 6801' have teethwhich enmesh. These sector gears may be driven by an axially rotatingshaft or by way of a gear linkage 6804, 6805.

A low profile mechanism may also be provided by a linear acting pusher6901, as shown in FIG. 69. The pusher 6901 is displaced by sets of gears6902, 6902' and 6903, 6903'. This arrangement eliminates the pusher arm,and thus may reduce the size of the mechanism. This embodiment may alsobe used with a skewed or inclined staple, further reducing the height orwidth of the stapler.

Example 8

The apparatus according to Example 1, including staples havingdimensions of 0.2×3×4 mm, having 30 staples per magazine, was used toanastomose healthy stomach and thin gut in a procedure known as agasteroenteroanastomosis, to bypass the pyloric sphincter. The stapleswere inserted in either a single line of staples or two adjacent rows ofstaples. A total of 50 experiments were performed using the stapler, onfresh cadavers.

In the procedure, a 50 mm horizontal incision was made in the left lowerquadrant, and the tissues dissected, exposing the stomach. The lowerposterior wall of the stomach was exposed, and a longitudinal incisionmade. In addition, a portion of descending duodenum, on the posteriorwall of the abdominal cavity was also exposed, and a longitudinalincision was made. The duodenum was then brought to a position near thegastric incision. The two incisions were approximately the same length.In order to fix the tissues with respect to the stapler, forceps areemployed to provide traction to the tissue and hold the layers together.The walls of the two lumens were everted, mucosal layers touching, andthe anterior walls of the incisions were initially stapled from top tobottom in a line approximately 3 mm from the cut edges. A second row ofstaples was then inserted next to the first, approximately 2 mm distalfrom the cut edge from the first row of staples, thus beingapproximately 5 mm from the cut edge. Next, the posterior walls werejoined midway through the incisions, from top edge to middle. For thisportion, the stomach wall incision was held in traction at an angle ofabout 20°-30° from the first incision. Finally, the incisions wereclosed by stapling from bottom edge to middle, completing thereanastomosis, in triangular fashion, to help ensure patency of thelumen. The outer row of staples was applied parallel to the incision,spaced every 5 mm. The inner row of staples was also spaced every 5 mm,aligned between the gaps in the outer row, in so-called "chess fashion".

In the above procedure, the tissues were cleanly and strongly connected.No cutting of the tissues by the stapling process was noted. Prior toclosing the incision, the strength of the anastomosis was determined bypalpation and gentle traction, and the closures were found to be strong.The closure was visually inspected, and the serosa were properlyaligned. After the closure was completed, the small bowel was filledwith a liquid. No leakage was noted of liquid from the incision.

The stapler according to the present invention allows wound closure ator near the incision edges, in the case of jagged edges, and theformation of comers and the use of controlled tension between staples ina closure, which helps to maintain the patency of the lumen ofanastomosed organs.

It should be understood that the preferred embodiments and examplesdescribed herein are for illustrative purposes only and are not to beconstrued as limiting the scope of the present invention, which isproperly delineated only in the appended claims.

What is claimed is:
 1. A stapler, comprising:(a) a staple advancingsystem for applying an advancing force to a plurality of "U" shapedstaples; (b) a guide, for maintaining said plurality of "U" shapedstaples parallel to each other along a feed axis, said guide having achannel cross section including a horizontal top portion, substantiallyperpendicular to said feed axis, and two semi-vertical portions belowsaid horizontal top portion, each having a plane oriented downwardlyinward at such an angle which does not cause plastic deformation of said"U" shaped staples inserted in said guide, said guide having an open endwherein said semivertical portions merge with walls having verticalportions which are substantially aligned with a vertical axis; (d) alower aperture, aligned with respect to said feed axis with saidvertically aligned walls; and (e) a displaceable staple ejector, fordisplacing one of said "U" shaped staples proximate to said open endthrough said lower aperture, without displacing an adjacent "U" shapedstaple.
 2. The stapler according to claim 1, further comprising:(a) amechanism producing an actuation signal; (b) an actuation signaltransmission system; (c) a displaceable former, for plasticallydeforming staple ends, said former being displaceable between a firstposition in which the former is substantially displaced along saidvertical axis from said lower aperture and a second position in whichthe former is substantially proximate to said lower aperture along saidvertical axis; and (d) control means for displacing said former from thefirst position to said second position and for displacing said stapleejector.
 3. The stapler according to claim 2, wherein said actuationsignal transmission system comprises a system selected from the groupconsisting of mechanical, electrical, pneumatic and hydraulic.
 4. Thestapler according to any of claim 1, wherein said staple advancingsystem for applying an advancing force comprises a helical springpressing against a staple feeding member.
 5. The stapler according toany of claim 1, further comprising a former arm and an ejector arm, saidformer arm and said ejector arms each being hinged with a return springat a point distant from said open end, wherein said control meanscomprises a displaceable sleeve riding over a portion of said pusher armand a portion of said former arm, depressing said pusher arm and saidformer arm during displacement.
 6. The stapler according to any ofclaims 1-3, further comprising a former arm and an ejector arm, saidformer arm and said ejector arms each being hinged with a return springat a point distant from said open end, wherein said control meanscomprises a displaceable sleeve riding over a portion of said pusher armand a portion of said former arm, depressing said pusher arm and saidformer arm during displacement, and wherein said staple advancing systemfor applying an advancing force comprises a helical spring pressingagainst a staple feeding member.
 7. The stapler according to any ofclaim 1, further comprising an end guide aligned with said verticalaxis, a first recess aligned with said vertical axis and a secondrecess, deeper than said first recess, aligned with said vertical axis,said lower aperture being aligned with said vertical axis and saiddisplaceable staple ejector being displaceable along said vertical axisin said second recess, and guided thereby.
 8. The stapler according toany of claim 1, wherein a staple in said guide has its legs elasticallydeformed to conform to the trapezoidal profile of said guide, and astaple exiting said longitudinal guide into said open end has its legsprojecting parallel to one another, abutting said vertical portions. 9.The stapler according to any of claim 1, further comprising a pluralityof staple guides and a plurality of lower apertures, for providing aplurality of simultaneously inserted staples.
 10. The stapler accordingto any of claim 1, further comprising a selectively engageable lock toprevent ejection of a staple.
 11. A method of attaching sheet-likematerials, comprising providing a stapler comprising:(a) a mechanismproducing an actuation signal; (b) an actuation signal transmissionsystem; (c) a staple cartridge having(i) a staple advancing system forapplying an advancing force to a plurality of "U" shaped staples; (ii) aguide, for maintaining said plurality of "U" shaped staples parallel toeach other along a feed axis, said guide having a channel cross sectionincluding a horizontal top portion, substantially perpendicular to saidfeed axis, and two semi-vertical portions below said horizontal topportion, each having a plane oriented downwardly inward at such an anglewhich does not cause plastic deformation of said "U" shaped staplesinserted in said guide, said guide having an open end wherein saidsemivertical portions merge with walls having vertical portions whichare substantially aligned with a vertical axis; (iii) a lower aperture,aligned with respect to said feed axis with said vertically alignedwalls; and (iv) a displaceable staple ejector, for displacing one ofsaid "U" shaped staples proximate to said open end through said loweraperture, without displacing an adjacent "U" shaped staple; placing thesheets to be attached along the vertical axis of the staple ejector,between the staple and the former; (d) a displaceable former, forplastically deforming staple ends, said former being displaceablebetween a first position in which the former is substantially displacedalong said vertical axis from said lower aperture and a second positionin which the former is substantially proximate to said lower aperturealong said vertical axis; and (e) control means for displacing saidformer from the first position to said second position and fordisplacing said staple ejector; displacing said former from the firstposition to said second position; and displacing said staple ejector.12. A method of attaching sheets according to claim 11, wherein saidformer is displaced in a first phase to compress the sheets and thestaple ejector is displaced in a second phase to eject said "U" shapedstaple and staple said sheets.
 13. A method according to claim 11further comprising the step of displacing said staple ejector away fromsaid former along said vertical axis in a third phase, during which astaple is released from said guide into said open end, with its legsspringing outward to contact said vertically aligned walls.
 14. Themethod according to claim 11, wherein said actuation signal transmissionsystem comprises a system selected from the group consisting ofmechanical, electrical, pneumatic and hydraulic.
 15. The methodaccording to any of claim 11, further comprising the step of applyingsaid advancing force by means of a helical spring pressing against astaple feeding member.
 16. The method according to any of claim 11,further comprising providing a former arm and an ejector arm, saidformer arm and said ejector arms each being hinged with a return springat a point distant from said open end, wherein said control meanscomprises a displaceable sleeve riding over a portion of said pusher armand a portion of said former arm, said displacing step comprisingdepressing said pusher arm and said former arm by displacing saidsleeve.
 17. The method according to any of claim 11, further comprisingproviding a former arm and an ejector arm, said former arm and saidejector arms each being hinged with a return spring at a point distantfrom said open end, wherein said control means comprises a displaceablesleeve riding over a portion of said pusher arm and a portion of saidformer arm, said displacing step comprising depressing said pusher armand said former arm by displacing said sleeve, and wherein said stapleadvancing system for applying an advancing force comprises a helicalspring pressing against a staple feeding member.
 18. The methodaccording to any of claim 11, further comprising providing an end guidealigned with said vertical axis, a first recess aligned with saidvertical axis and a second recess, deeper than said first recess,aligned with said vertical axis, said lower aperture being aligned withsaid vertical axis and said displaceable staple ejector beingdisplaceable along said vertical axis in said second recess, and guidedthereby.
 19. The method according to any of claim 11, further comprisingthe step of elastically deforming the legs of a staple in said guide toconform to the trapezoidal profile of said guide, and expelling a staplefrom said longitudinal guide into said open end so that its legsprojecting parallel to one another, abutting said vertical portions.